1. Field of Invention
The present invention relates to an interactive video distribution system. More particularly, the invention relates to a method and apparatus for increasing the fault tolerance at each of a plurality of head-ends in an interactive video distribution system.
2. Description of the Background Art
Video distribution systems established by a service provider typically utilize a plurality of cable head-ends. A head-end serves as a distribution point for a designated “neighborhood” of subscribers. Subscriber requests for video information such as movies, are made by a subscriber using a remote control device to select from a menu of available titles displayed on a display device. After selection by a subscriber, a request for the selected video information is sent to the local head-end supporting the subscriber.
The requested video information is then transmitted from the head-end to the subscriber for viewing. A typical head-end comprises a video server system that contains subsystems for managing, storing and distributing the video content.
In a system comprising a large number of subscribers, each head-end experiences a substantial level of activity. This typically results in delays in responding to subscriber requests. In addition, data processing and/or transmission errors increase as the demand placed upon the head-end increases. For example, physical hardware errors due to component failures, may result in unacceptable viewing experiences for the subscriber. In some circumstances, a single point of failure may occur that compromises the entire head-end, thereby disrupting video sessions to most, if not all of the subscribers coupled to that particular head-end.
Therefore, it is seen to be desirable to provide more robust head-end functionality within an information distribution system such that delivery of services to subscribers is enhanced. Specifically, it is seen to be desirable to distribute head-end processing functions among a plurality of head-end devices in such a manner as to increase fault tolerance and, ideally, to reduce any single point of failure.